Device on jet weaving looms



DEVICE ON JET WEAVING LOOMS Filed Jan. 23, 1957 2 Sheets-Sheet 1 INVENTORS. Roberl Op/efaF BY BI eZZS/av fiwiiafe/f May 10, 1960 R. OPLETAL ET AL 2,936,002

DEVICE ON JET WEAVING LOOMS Filed Jan. 23, 1957 2 Sheets-Sheet 2 QmQ nnvrcs JET waavnso LOOMS Robert Opletal, Bl'IlO-KOlllill, and Bretislav Dvoracek,

Brno-Zabovresky, Czechoslovakia, assignors to Vyzkumny ustav tvarecich strain a technolcgie tvareni, Brno, Czechoslovakia Application January 23, 1957, Serial No. 635,899

8 Claims. (Cl. 139-127) The present invention relates generally to weaving looms of the kind in which weft threads are inserted into the shed by means of an air jet.

In weaving looms of this type a closing member, such as an actuating valve, is provided in the pressure air conduit in front of the nozzle or jet, said valve being opened intermittently, preferably by means of a revolving actuating cam, only when a weft thread is to be blown into the shed, whereupon the valve is closed again.

When the weaving loom is stopped, either by the operator or by the weft stop motion, and happens to come to rest in a position, in which the valve is open, pressure air keeps flowing out of the nozzle; and apart from a loss of pressure air, the air stream or jet may cause breakage of the weft thread by disintegration of the latter if air is allowed to flow continuously out of the nozzle.

The above drawbacks are removed according to the invention by a device including a control apparatus interposed in the conduit for supplying pressure air to the nozzle at a location in front of the actuating valve, said control apparatus being operated by a rotating control cam and adapted to discontinue the supply of pressure air to the actuating valve, if the weaving loom comes to rest with the actuating valve in its open position.

The above, and other objects, features and advantages of the invention will be apparent in the following detailed description of an illustrative embodiment thereof which is to be read in connection with the accompanying drawings, wherein:

Fig. 1 is a diagrammatic view of a device embodying this invention, which is shown in the condition corresponding to the stopping of the associated loom in a position where the actuating valve is held open;

Fig. 2 is a view similar to that of Fig. 1, but showing the condition of the device during closing of the actuating valve, when the loom is being operated; and

Fig. 3 is another view similar to that of Fig. 1, but showing the device during opening of the actuating valve when the loom is being operated.

Referring to the drawings in detail, it will be seen that, in accordance with the invention, a control device or apparatus K is interposed between a source of air under pressure (not shown) and an actuating valve 3 which controls the exhaust of the air jet through a nozzle 1.

Pressure air enters the control device K through an inlet conduit A and leaves the device K through a con duit 4 having the actuating valve 3 interposed therein. The actuating valve 3 is operated by an actuating cam 2 mounted on a rotatedshaft 16, the cam 2 being engaged by a follower roller 18 which is mounted on the rod or stem of valve 3. When the weaving loom is stopped, with the actuating valve 3 in open position, as in Fig. 1, it is the function of the control device K to close the supply conduit to the actuating valve.

The control device is operated by means of a rotating control cam 5, mounted on a shaft 17, which rotates in synchronism with the rotation of shaft 16 carrying cam 2 of the actuating valve. The cam 5 is engageable by a follower roller 14 mounted for rotation on a valve rod 12' guided in the control device K and carrying a valve 6. The cam 5 controlling the valve 6 is formed with a portion of relatively small radius permitting the upward closing of the valve 6, and extending over an angle a, which is approximately equal to the angular extent of the operative elevated or enlarged radius part of the cam 2, by means of which the actuating valve 3 is opened, and which amounts to about Connected to the valve 6 is a piston rod 13 which is guided in the control device by a seal 19 and carries a piston 8 movable in a cylinder 7. The piston 8 is provided with at least one bore 9 which is covered at its upper end by a disc 10 urged downwardly against the piston 8 by a spring 15. Housed in the lower space C of the cylinder 7 is a spring 11 acting upwardly against the piston 8, and tending to close the valve 6. The piston 8 is fitted in the bore of the cylinder 7 with a certain play, so that oil or another medium, with which the cylinder is filled, may pass around the piston 8 between the lower space C of the cylinder and the upper space D of the cylinder.

When the piston 3 is tightly fitted in the cylinder '7, the wall of the piston 8 or of the cylinder '7 may be provided with a narrow axial groove to permit the flow of the oil or other medium between the spaces C and D.

The device according to the invention operates as follows:

When the weaving loom is operating, the shafts 16 and 17, and the cams 2 and 5 thereon are synchronously rotated, and the cams 2 and 5 are angularly positioned relative to the respective shafts so that the radially enlarged portion of cam 2 engages the follower roller 13 to open the actuating valve 3 during a period in each rotational cycle when the radially reduced portion of the cam 5 faces toward the cam follower roller 14 on the stem 12 of valve 6, as in Figs l and 3. During the remainder of each rotational cycle or revolution of the cam 2, that is, when the follower roller 18 of actuating valve 3 is engaged by theportion of cam 2 having relatively small radial dimensions to permit the closing of actuating valve 3, the cam follower roller 14 of the stem 12 of valve 6 is engaged by the portion of cam 5 having a relatively large radial dimension so that valve 6 is moved downwardly to its open position, as in Fig. 2. It will be apparent that, during downward movement of valve 6 to its open position, the corresponding downward movement of the piston 8 will cause displacement of oil from the lower space C to the upper space D of the cylinder 7. Since the disc 10 is held downwardly on the top of piston 8 by the yieldable force of the spring 15, the downward movement of cylinder 8 will cause the oil in the lower space C to lift up the disc 10 and thereby uncover the bore or bores 9 in order to provide a passage of increased area through which the oil can flow from the lower space Cto the upper space D during downward movement of piston 8, as shown in Fig. 2.

When the cam 2 again returns to the position for opening the actuating valve 3 during normal operation of the associated weaving loom and the cam 5 is correspondingly positioned to permit upward movement of the valve 6 to its closed position, such upward movement of the valve 6 is slowed by the resistance of the oil to passage 7 oil in cylinder] offers a relatively large resistance to j i upward movement of the piston 8 by the spring 11, and

a relatively small resistance to downward movement of the piston 8 by the action of the cam 5.

In the device K embodying the invention, the clearance between piston 8 and cylinder 7, or, in the case of a tight fitting piston 8, the cross-sectional area of the groove provided either in the circumferential surface of the piston 3 or in the inner surface of the cylinder 7, the strength of the spring 11 and the viscosity of the oil contained in the cylinder 7 are selected so that, during normal operation of the associated loom, the resistance oifered by the oil to upward movement of valve 6 from its opened position (Fig. 2) to its closed position (Fig. 1) will slow such upward movement sufiiciently to prevent closing of the valve 6 during the time when the portion of the cam of relatively small radial extent is disposed at the bottom of the cam, that is, in a position to be engaged by the follower roller 14. Thus, during normal operation of the loom, the cams 2 and 5 are continuously rotated so that the actuating valve 3 is repeatedly opened and closed, while the control valve 6 merely fluctuates between more or less opened positions, as in Figs. 2 and 3, respectively.

However, when the operation of the associated weaving loom is halted and the loom comes to rest with the earn 2 disposed to hold the actuating valve 3 in its opened position, as in Fig. l, the cam 5 will come to rest with its radially reduced portion disposed for engagement by the follower roller 14 on stem 12 of valve 6, so that the spring 11 can then slowly move the piston 8 upwardly against the resistance of the oil in cylinder '7, and thereby efiect closing of the valve 6. Thus, even though the actuating valve 3 is in its open position when the associated loom comes to rest, the valve 6 is automatically closed in order to interrupt the supplying of air under pressure through the conduit 4' to the nozzle 1.

When operation of the loom is recommenced, the turning of cam 5 will again effect the downward movement of valve 6 to its open position, and the valve 6 will thereafter be retained in a more or less opened position, as described above, during normal operation of the loom.

Although an illustrative embodiment of the invention has been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to that precise embodiment, and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention, except as defined in the appended claims.

We claim:

1. In a jet weaving loom, in which weft threads are inserted into the shed by means of an air jet; a device comprising a nozzle for emitting an air jet blowing the weft thread into the shed, a conduit for. supplying air under pressure to said nozzle, an actuating valve for controlling the admission of air under pressure from said conduit into the nozzle, an actuating cam controlling the opening and closing of said actuating valve and rotated in response to operation of the loom, control means interposed in said conduit in front of said actuating valve, and a control cam operating said control means and rotated in synchronism with said actuating cam, said control means automatically interrupting the supply of air under pressure through said conduit to said actuating valve when the weaving loom is stopped with said actuating valve in its open position.

2. In a jetweaving loom, in which weft threads are inserted into the shed by means of an air jet; a device comprising a nozzle for emitting an air jet blowing the weft thread into the shed, a conduit for supplying air under pressure to said nozzle, an actuating valve for controlling the admission of air under pressure from said conduit into the nozzle, an actuating cam controlling the opening and closing of the actuating valve and rotated in response to operation of the loom, control means interposed in said conduit in front of said actuating valve and l l r including a control valve movable between open and closed positions, a control cam rotated in synchronism with said actuating cam and operative to periodically move said control valve to said open position and, in the intervals therebetween, to permit movement of said control valve toward said closed position, a piston rod extending from said control valve and carrying a piston, a cylinder filled with a liquid and receiving said piston, and a spring acting against the piston and urging the latter in the direction for moving said control valve to said closed position, said liquid in said cylinder slowing the movement of said control valve sufficiently to avoid closing of said control valve during said intervals between the periodic opening movements of the control valve.

3. In a jet weaving loom, in which weft threads are inserted into the shed by means of an air jet; a device comprising a nozzle for emitting an air jet blowing the weft thread into the shed, a conduit for supplying air under pressure to said nozzle, an actuating valve for controlling the admission of air under pressure from said conduit into the nozzle, an actuating cam controlling the opening and closing of the actuating valve and rotated in response to operation of the loom, control means interposed in said conduit in front of the actuating valve and including a control valve movable between open and closed positions, a control cam rotated in synchronism with said actuating cam and operative to periodically move said control valve to said open position and, in the intervals therebetween, to permit movement of said control valve toward said closed position, a piston rod extending from saidcontrol valve and carrying a piston, a cylinder filled with a liquid and having said piston movable therein, and a spring acting against the piston and urging the latter in the direction for moving said control valve to said closed position, said piston dividing said cylinder into two spaces, and said piston and cylinder defining narrow flow passage means therebetween connecting together said two spaces of the cylinder so that the liquid in said cylinder slows the movement of said control valve toward said closed position by said spring to avoid closing of the control valve during said intervals between the periodic opening movements of the control valve by said control cam while the loom is operating.

4. In a jet weaving loom, a device as in claim 3, wherein said narrow flow passage means is formed by a radial clearance between the wall of the cylinder and the outer surface of the piston.

5. In a jet weaving loom, in which weft threads are inserted into the shed by means of an air jet; a device comprising a nozzle for emitting an air jet to blow the weft thread into the shed, a conduit for supplying air under pressure to the nozzle, an actuating valve for controlling the admission of air under pressure from the conduit into the nozzle, an actuating cam controlling the opening and closing of the actuating valve and being rotated in response to operation of the loom, control means interposed in said conduit in front of the actuating valve and including a control valve movable between open and closed position, a control cam rotated in synchronism with said actuating cam and operative to periodically move said control valve to said open position when said actuating valve is closed, and, in the intervals when the actuating valve is open, to permit movement of said control valve to said closed position, a piston rod extending from said control valve and carrying a piston, a cylinder filled with a liquid and having said piston movable therein, a spring acting against the piston and urging the latter in the direction for moving said control valve to its closed position, said piston and cylinder having a clearance therebetween through which said liquid can flow upon movement of the piston, said piston having at least one axial bore extending therethrough, and a resiliently loaded disc normally covering said bore at the end of the latter facing in the direction of movement of said piston causing closing of said control valve, so that said resiliently loaded disc is displaced to piston in the direction for opening said control valve.

6. In a jet weaving loom, in which weft threads are inserted into the shed by means of an air jet; a device comprising a nozzle for emitting an air jet to blow the weft thread into the shed, a conduit for supplying air under pressure to said nozzle, an actuating valve for controlling the admission of air under pressure from the conduit into the nozzle, an actuating cam for controlling the opening and closing of the actuating valve and rotating in response to operation of the loom,control means interposed in said conduit in front of the actuating valve, a control cam for operating said control means and being rotated in synchronism with said actuating cam, said control means stopping the supply of air'under pressure to the actuating valve when the weaving loom is stopped with the actuating valve in its open position, a trough-like portion on the control cam for permitting the closing of the control valve, a projecting portion on the actuating cam effective to open the actuating valve, the angular extents of said trough-like portion of the control cam and of said projecting portion of the actuating cam each amounting to about 9'0".

7. In a jet weaving loom in which weft threads are inserted in the shed by means of an air jet; a device comprising a nozzle for emitting an air jet to blow the wefit thread into the shed, a conduit for supplying air under pressure to said nozzle, an actuating valve for controlling the admission of air under pressure from said conduit into said nozzle, an actuating cam for controlling said actuating valve and being rotated in response to operation of the loom to periodically open and close said actuating valve, a control valve interposed in said conduit and movable between open and closed positions, a control cam, rotated in synchronism with said actuating cam and operative to move said control valve to said open position of the latter during each period when said actuating valve is closed and to permit said control valve to move to said closed position during each period when said actuating valve is open, spring means urging said control valve to said closed position, and means effective to slow the movement of said control valve to said closed position so that the time required for movement of said control valve to said closed position from said open position is greater than the period during which said actuating valve normally is open, and said control valve can move to said closed position only when operation of the loom is halted with said actuating valve open by said actuating cam.

8. In a jet weaving loom; a device as "in claim 7, wherein said means effective to slow the movement of said control valve includes a cylinder containing a liquid, a piston connected to said control valve and movable in said cylinder, said piston and cylinder defining a restricted passage therebetween for permitting the flow of said liquid therethrough upon axial displacement of said piston relative to said cylinder, said piston having an additional passage therethrough, and valve means normally closing said additional passage and opening the latter only in response to movement of said piston in the direction corresponding to opening of said control valve so that the resistance of the liquid in said cylinder to axial displacement of said piston is reduced during movement of the latter in said direction corresponding to opening of said control valve.

References Cited in the file of this patent UNITED STATES PATENTS 

